1. Field of the Invention
The present invention relates to wireless communication systems and, more particularly, to an implementation of an enhanced call return feature in a wireless telephone network.
2. Description of the Related Art
Contemporary telephone subscriber services may be divided into two major categories: (1) Wire line services; and (2) Wireless services. A wire line service typically utilizes a wired network of telephone cables or conductors. In other words, in a wire line network, telephone signals are transmitted over a physical wire path of, typically, copper conductors or wires. On the other hand, wireless services (e.g., cellular telephone service, personal communications service (PCS), etc.), as the name suggests, employ wireless means to carry telephone signals through the air (i.e., instead of wires) between a caller and callee. Although a telephone call originating in a wireless network may ultimately be transmitted through a wire line network to reach its destination, the principal mode of communication nonetheless still remains wireless in the wireless network. Typical examples of wire line telephone networks include the POTS (Plain Old Telephone System) and the more advanced PSTN (Public Switched Telephone Network). Some examples of land-based wireless telephone networks include the cellular (or mobile) telephone network and the personal communications network (PCN).
Both of the above-mentioned subscriber telephone services are governed by a number of corresponding regulatory standards and protocols that define how calls are to be treated in the respective system and which subscriber services may be provided. Some wire line service standards and protocols include the AIN (Advanced Intelligent Network) standard which may be considered as an upgrade to the SS-7 (signaling system number 7) standard, and the Internet Protocol (IP) for Internet-based telephony. Wireless telephone communication is also governed by a number of different standards and protocols, including the second generation TDMA (Time Division Multiple Access) air interface standard (popularly known as the IS-136 standard) and the wireless intersystems operation standard (alternately referred to as the IS-41 or the TIA/EIA-41 standard), both of which may be considered part of the WIN (Wireless Intelligent Network) standards.
The AIN protocol for the wire line network allows a telephone service provider to offer a variety of service options to a telephone line subscriber. Some of the services that may be offered by a telephone service provider include the telephone number portability service, the calling name service, the voice mail service, and the call return service. The call return feature allows a user (i.e., telephone line subscriber) to dial an access code, e.g., *69, to place a call to the calling party that last called the user's telephone number. This service is useful in a number of situations, e.g., when the calling party hangs up without giving the user a chance to pick up the phone, or when the user is aware of the phone call but unable to reach the phone and the calling party does not leave any message for the user.
Presently, a similar call return feature is absent for the subscribers of wireless telephone services. It is therefore desirable to implement the call return feature in wireless telephone networks.